Hi, I’m using the 8ch 4-20mA Receiver and I wanted to make sure the Raspberry Pi I2C Bus could detect the correct addresses for it. The jumper positions are as sent by factory, so the MCP3428s should be set as 0x68 and 0x6E. However, when I run i2cdetect, those addresses aren’t found, and instead I see the first 10 addresses of the I2C bus - as shown here:
There are no other devices connected, and when removed the bus returns to all blank. When connecting other devices (say, the 4ch relay card), the correct address is displayed, so the Pi’s bus appears to be functioning normally. Is something wrong with the MCPs, the receiver, or am I misinterpreting the operation of the board?
Thanks
I’m not using the NCD Pi Adapter- does it provide any needed functionality other than connecting to the I2C pins on the Pi? I’m using the same setup with the 4ch I2C relay board and there are no issues.
Does your master have i2c pull-ups?
if not connect the pull-up on MCP3428 board.
Also, keep in mind the MCP3428 i2c is running at 5V and RPI is running at 3.3C ( if you are not using ncd i2c shield)
It seems I was misinformed that the RasPi had built in pull ups for the I2C bus, but I configured the Receiver to use its onboard pull-ups and it is now detecting the addresses properly. Also, now that I see the NCD adapters do level shifting, I will be ordering one.
Thanks!
